CNR NANO - Istituto Nanoscienze Consiglio Nazionale delle Ricerche

- 09.09.2021 - NANO COLLOQUIA 2021 S3 Seminar Laura Bellentani
Date and Time: Semptember 9, 2021 - 15.00

ONLINE https://global.gotomeeting.com/join/159366589

Speaker: Laura Bellentani

Title: The IQUbits project for quantum computing in Si and SiGe MOSFETs

Abstract:The IQUbits project for quantum computing in Si and SiGe MOSFETs Among the possible frameworks to encode quantum information, semiconductor-based implementations present the highest potential in terms of scalability and compatibility with the current nanoelectronics industry. Under the umbrella of EU-H2020 projects, IQubits[1] focuses the technological effort on the formation of single-electron/hole quantum dots in traditional Si and SiGe CMOS devices, where spin qubits are monolithically integrated with the control-readout circuitry on the same die. The partnership involves physicists and engineers from CNR-NANO-S3 in Modena, the University of Toronto in Canada, the Applied Materials company in Reggio Emilia, the Aarhus University in Denmark, the National Institute for Research and Development in Microtechnologies in Romania, and the Foundation for Research and Technology in Greece.

Si has been recognized as an excellent host material for quantum computing devices thanks to the weak hyperfine interaction between the spin qubit and the nuclear spins, which is the main source of decoherence in III–V compound semiconductors. The experimental characterization of a 22-nm FDSOI pMOSFETs[2] has recently proved QD formation in the Si/SiGe channel up to a temperature of 1.2 K. In these transistors, confinement energies of the QD can be controlled by top gates, while the backgate formed in the Si substrate tunes the interdot coupling. Further, fast qubit operations and device scalability are fostered by the possibility to implement the EDSR protocol for a fully-electrical control of the spin and by the feasibility of readout schemes based on gate reflectometry.

This talk will address the work of the CNR-Nano unity within IQubits consortium to theoretically demonstrate the formation and manipulation of hole spin qubits in Si MOSFETs. We implemented a multi-scale approach for qubit simulation based on the 6x6 k.p method and full configuration interaction technique to characterize single and double QDs in the one- and few-hole regime. Our first results concern the characteristic Larmor and Rabi frequencies of single-hole spin-qubit operations in scaled prototypes of Si pMOSFETs[3]. Future perspectives involve the theoretical modeling of intra- e inter-band Coulomb integrals for holes in Silicon nanostructures and the simulation of double quantum dot systems.

[1]https://www.iqubits.eu/
[2]S.Bonen et al., IEEE Electron Device Letters 40, 127-130, (2019)
[3]Bellentani et al., arXiv:2106.04940 (2021)

Host: Massimo Rontani segreteria.s3@nano.cnr.it.